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neonblack
11-29-2012, 08:23 PM
What type circular saw blade is best for cleanest mdf cuts (60 tooth, 80 tooth, 140, etc.)?

nudels
11-29-2012, 08:27 PM
the higher the tooth count, the finer the cut

Serpent710
11-29-2012, 08:49 PM
or if your saw has some *** to it you can cut just fine with a lower tooth blade as well and save $

Kingstroker
11-29-2012, 08:57 PM
Freud TCG blades

Iosias
11-29-2012, 09:00 PM
If you have a worm-drive saw any would cut fine in mdf. Regular light weight one go with a higher tooth count and don't bog the saw.

Kingstroker
11-29-2012, 09:09 PM
if you clamp a straight piece of 1/4"-3/8" plywood or MDF to to your work and follow it with the edge of the saw base it will cut smooth as glass

nudels
11-29-2012, 09:29 PM
pretty sure he's asking what blade yields the finest/most exact edge, guys.


Cutting MDF Compared to Plywood

Both MDF and Plywood can be very tough on the cutting tools. This is why it is important to use saw blades that are specifically designed for cutting MDF and Plywood. Below is a link to some tools specially designed for cutting MDF and Plywood along with some helpful tips on how to choose a saw blade for cutting MDF and Plywood. The rest of this article explains why MDF and Plywood have such a high wear on cutting tools and the differences bewteen the two materials.

MDF is much harder on tools than plywood is for a variety of reasons.

The density – especially the varying density (see below)
The mechanism of separation. Plywood shears while MDF ruptures.
The amount and kinds of fiber
The amount of glue and additives used to stretch it.
MDF is harder on cutting tools for several reasons.

There is just more material being cut. Typically MDF is heavier than plywood because MDF uses wood fibers and then compresses them. (See below)
Plywood uses peeled wood while MDF can use a variety of fibers some much more abrasive.
Plywood and MDF can both use the same woods. However in plywood the cells are open or hollow. In MDF the cells have been compressed flat. Cutting hollow a straw is easier than cutting a solid piece of plastic because you can cut the straw one wall at a time.
The binder is distributed differently in the two materials. In plywood the binder is largely in the overlapping sheets. MDF can be considered binder with particles in it.
In analysis of worn tools we see several things.

Just the amount of material being cut.
MDF is more abrasive because it denser. When cutting the fibers are severed but the cut material rubs on the side of the tooth causing wear similar to the effect of a stiff bush versus a soft brush.
MDF seems to trap more heat in the cut and heat affects the saw tips. Again this is a natural property of the density and the glue distribution.
Suppositions

It is widely believed that MDF is “grabbier” on cutting tools and tests with ammeters have seemed to confirm this. MDF draws more power than wood or plywood.
It is widely believed that the glue in MDF is stretched with a clay like binder much as clay is used in paper. This binder is much more abrasive than wood as clay is technically fine sand.
MDF is made of wood fibers and any source can be used. Although the fibers are broken down into cells they retain many of their base properties. Bamboo cells have different properties than fir cells.


Tips for choosing a saw blade for cutting MDF, Plywood, and particle board:

Buy a triple chip blade or an ATB blade with a 10 or 15 degree hook.
A higher tip count will give you better cuts in MDF, Plywood, and Particle board.
Make sure the board is completely supported during the whole cut - absolutely no overhang without support.
Feed the material absolutely straight and steady against a guide. 2 x 4’s are not really good guides. You can greatly affect cut quality, both good or bad, by how you feed. Experiment with scrap material to make sure you are feeding correctly.
Keep the blade sharp. Plywood and MDF are glued together. The glue uses clay as a filler. Clay is very small rocks so it really wears saw blades.

Kingstroker
11-29-2012, 10:32 PM
TCG tipped blades are designed for laminate/mdf, the method I described helps insure smooth cuts from circular saws. In other words, it's not just the blade but how you use it. For 10" blades this usually means 60-80 tpi. Probably in the 24-36 tpi range for a 7 1/2" blades.

neonblack
11-30-2012, 09:07 PM
if you clamp a straight piece of 1/4"-3/8" plywood or MDF to to your work and follow it with the edge of the saw base it will cut smooth as glass
Yes, I'm going to do that but the cut can still turn out rough according to the blade you're using. Yes, low tooth blades will rip it good and not smooth is my experience with harder, natural woods and fiberboard.

Thanks, this has helped me a lot. I hate going to Home Depot and searching and searching for the right tool, brand, material, etc. and blow my project due to wrong tool.

-01limited-
11-30-2012, 09:17 PM
Lol at making a simple cut into rocket science. Just cut it and run some sand paper over it after and it'll look just fine. And hell a lot of people are just going to cover it up anyways.

keep_hope_alive
11-30-2012, 09:32 PM
MDF, like other engineered woods (OSB, particle board, plywood, etc.) are adhered using resin. a formaldehyde resin is commonly used because it is cheap. it's also why the "off-gassing" of new wood is toxic and why you do NOT want to breathe in those airborne fibers. a respirator is strongly recommended when cutting MDF. I use a cartridge filter (paint fume type) respirator, same as when i work with fiberglass.

Kangaroux
11-30-2012, 09:33 PM
Are the Diablo brand blades and bits from homedepot worth the cash? The blade on my table saw has only been replaced once and that was years ago, was eyeing the 60 tooth diablo for $25.

Kingstroker
11-30-2012, 11:13 PM
Toxicity is always a concern not only with mdf, hdf, particle board and treated plywood but also some exotic wood species. Diablo are construction grade blades and will suffice, like everything else, you get what you pay for. They are a big step up from B&D and DeWalt. I've built everything you can build with wood(cabinets, furniture, entertainment centers, houses)in the last 30 years except speaker enclosures , that I know nothing about. Think of wood working tools as audio equipment, can't get HAT quality from Pyle but sometimes CDT will do. (Only examples from a noobs perspective, no offense intended)

fasfocus00
11-30-2012, 11:22 PM
i only use the Diablo 80 tooth blade, cuts clean and last a long while.

av83
11-30-2012, 11:29 PM
What type circular saw blade is best for cleanest mdf cuts (60 tooth, 80 tooth, 140, etc.)?

spent 5$ at harbor freight on a 142 tooth plywood blade. worked great. However, I only use my circ saw 5 or so times a year, and it's only for cutting mdf for enclosures.

maylar
12-01-2012, 10:45 AM
the higher the tooth count, the finer the cut

Yes, and the more power the saw needs. Too many teeth and the saw will bog down, bind, and burn the wood. So it depends on the saw.


Freud TCG blades

My choice too.

DevilDriver
12-01-2012, 10:50 AM
I have been a residential carpenter for 15 years Diablo 40 T is prob your best bet

nudels
12-01-2012, 12:52 PM
Yes, and the more power the saw needs. Too many teeth and the saw will bog down, bind, and burn the wood. So it depends on the saw.


yeah, if you like to go balls-to-the-wall and force the blade to take on more material than it can handle.

typically, the power needed to cut mdf *or any other material, for that matter* varies by how fast you feed the material combined with your blade depth, thus making the actual tool for the job a 'preference' as 'opposed to necessity' such as the question of blade, to suit the end result,.. but the question wasnt about a saw, was it?

*edit, there was an old saying i took heed of when i first started doing carpentry, which was; "let the blade cut the material, not the carpenter"

Kingstroker
12-01-2012, 01:21 PM
"typically, the power needed to cut mdf varies by how fast you feed the material combined with your blade depth, thus making the actual tool for the job a 'preference' to suit end result,.. but the question wasnt about a saw, was it?"

You may get away with slowing down just a little but any more than just a little "typically" means your blade is getting dull or bade is too thick for saw hp(use a thin kerf)
If you are cutting 3/4" stock of almost anything and you have to slow down your feed rate very much, you tend to build up heat. This will: burn your stock, dull your blade, create a varnish like coating of burnt material that builds up on your blade which will cause a uneven cut or even cause it to stop cutting. The more dense the material is the more likely all this will happen. Any info other than type of blade was added to be helpful.

maylar
12-02-2012, 10:49 AM
yeah, if you like to go balls-to-the-wall and force the blade to take on more material than it can handle.

Not true. If you go too slow you'll burn the work and warp the blade. The blade must be matched to the saw and to the job at hand for optimum results.


typically, the power needed to cut mdf *or any other material, for that matter* varies by how fast you feed the material combined with your blade depth, thus making the actual tool for the job a 'preference' as 'opposed to necessity' such as the question of blade, to suit the end result,.. but the question wasnt about a saw, was it?

My point is only that you need to consider the saw when you choose a blade. The CMT Tools blade charts used to have a "minimum recommended HP" column for 10" blades. The more teeth and wider the kerf the more HP is required to get good results.